WJEC Geography Practice Test 2026 - Free Geography Practice Questions and Study Guide

Percolation is the downward movement of water through soil and rock driven by gravity. After rain infiltrates the surface, the water moves through pore spaces in the soil, continuing downward into deeper layers. The coffee-dripping analogy fits because gravity pulls the liquid through a porous medium, just as water moves down through soil. Infiltration is the initial entry of water into the soil from the surface, groundwater flow is movement through the saturated zone in the subsurface, and interception is rainfall captured by vegetation that may not reach the soil at all.